don't worry about their health - they won't be swallowing what they chew as rats' mouths can close off behind their front teeth to prevent them eating what they gnaw. But the escapology must stop!
the critter cage is all metal, but is a horrible cage - and pretty small but ok for 2 girls for a bit, but I've only used it as a holiday or hospital cage for very small numbers. https://www.amazon.co.uk/Critter-All-Metal-Cage-Medium/dp/B006LPTMH0
the Aventura says its all metal, but you'd need to modify it to stop substrate falling out. http://www.littlepetwarehouse.co.uk/products/metal-aventura-huge-metal-rat-ferret-chinchilla-cage.html
Many people get trays made specially to replace plastic ones or get plastic sides made to deepen the base and stop substrate falling ou- I've not had to, so am not sure who to suggest, but this might be your best option, depending on timescale!